I will be recieving my FAB 10 lower soon and I have an Idea. I want to make my lower look like it will accept detachable magazine. The way I plan to do this is to cut a real 30rd.mag in half remove the spring and follower then use some epoxy or something strong to glue the partial mag onto the reciever. It might not work it depends on weither I can find a strong enough adhesive. The question is would this be legal, since it is pureley cosmetic? I think it is what do you think? Any suggestions on some good adhesive?

it would be perfectly legal. Now the question is that do you have 30 round magazine? If not then you could buy one and ask politely to the person selling you the magazine to remove the feeding lips off the magazine so it no longer acts as an ammunition feeding device. Then mag will no longer be a magazine and thus no longer restricted.
hope that helps, and good luck on your project fellow oppressed Kalifornian. [:D]
I was also thinking, it would be a little more work but what if you attach some kind of bracket to the bottom of your FAB10 then attach/screw the magazine housing to that bracket - that would work better than any adhesive and last longer.

Having the 30 round magazine helps. I haven’t seen a FAB10 up close yet but I believe that on the left hand side of the receiver you will find a hex screw holding the magazine where the magazine catch hole was. Really there should to be someway you can take the magazine out for cleaning and routine maintenance. So how do you plan to configure your FAB10? I’m pretty sure I’m going to build my in a pre-ban configuration, the only problem with doing that is I could not move the components to a magazine based receiver unless both the federal law and the state laws were shot down somehow. But that probably won’t ever happen. So what about you?

If you have to live in CA ... this is a pretty cool idea to make a FAB10 look better.
I would consider using a shortened 20 rnd mag instead of the 30 though. The 20 is more convenient for benchrest shooting and won't get in the way, besides the leverage is less if you happen to contact the fake mag extension on anything - this might prevent tearing the mag off the lower.
Just my .02
Ryan

I plan to build mine in a pre and post ban configuration at least temporarily. I have a 16 inch postban upper with a Y-comp muzzlebrake. I am going to use a 4 position telestock and a DPMS parts kit. In the future I will either get a pre ban M4 flat top upper, or I might get a bird cage style brake installed on my current upper. Right now I use my upper on a single shot DPMS lower. I cant wait to haved some semi-auto fun. I thought about using a 20rd. mag for bench shooting, but I really like the way an ar looks with a 30rd. mag, and I haved shot a few AR's at the range with thirty rounders and Harris bipods with no problem, so thats what I'm going with.

The magazine that is built into the FAB 10 is riveted to the lower receiver in addition to being held in place with a large set screw. The rivet needs to be drilled out in order to remove the mag. How do I know this? I have a FAB 10 which I received a few weeks ago.
The take down holes need some filing in order to mate with the upper. Otherwise, it is well made and nice to know that I now have a California legal AR-15 otherwise known as a FAB-10